Magnetoresistance effect element

Abstract

A magnetoresistance effect element includes a first ferromagnetic layer, a second ferromagnetic layer, and a nonmagnetic layer. The nonmagnetic layer is between the first ferromagnetic layer and the second ferromagnetic layer. At least one of the first ferromagnetic layer and the second ferromagnetic layer is a Heusler alloy layer. The nonmagnetic layer includes a first region and a second region in a plane. Both of the first region and the second region are formed of a metal. The second region is different in constituent material from the first region. The second region has a crystal structure of a body-centered cubic lattice structure (bcc).

What is claimed is: 
     
       1. A magnetoresistance effect element comprising:
 a first ferromagnetic layer, a second ferromagnetic layer, and a nonmagnetic layer, 
 wherein the nonmagnetic layer is between the first ferromagnetic layer and the second ferromagnetic layer, 
 wherein at least one of the first ferromagnetic layer and the second ferromagnetic layer is a Heusler alloy layer, 
 wherein the nonmagnetic layer includes a first region and a second region in a plane, 
 wherein both of the first region and the second region are formed of a metal, 
 wherein the second region is different in constituent material from the first region, and 
 wherein the second region has a crystal structure of a body-centered cubic lattice structure (bcc). 
 
     
     
       2. The magnetoresistance effect element according to  claim 1 , wherein at least a part of the second region penetrates the nonmagnetic layer in a stacking direction. 
     
     
       3. The magnetoresistance effect element according to  claim 1 , wherein the second region contains any element selected from the group consisting of Mg, V, Cr, Nb, Mo, Ta, and W. 
     
     
       4. The magnetoresistance effect element according to  claim 3 , wherein the second region is formed of an alloy containing V or Cr. 
     
     
       5. The magnetoresistance effect element according to  claim 1 , wherein a lattice matching degree between the Heusler alloy layer and the second region is within 4%. 
     
     
       6. The magnetoresistance effect element according to  claim 1 , wherein, in the Heusler alloy layer, crystals are mainly oriented in a (001) or (011) direction. 
     
     
       7. The magnetoresistance effect element according to  claim 1 , wherein the second region accounts for 10% or more and 70% or less of the nonmagnetic layer. 
     
     
       8. The magnetoresistance effect element according to  claim 1 , wherein the second region accounts for 10% or more and 50% or less of the nonmagnetic layer. 
     
     
       9. The magnetoresistance effect element according to  claim 1 ,
 wherein the Heusler alloy layer is represented by a composition formula Co 2 Y α Z β , 
 wherein the Y is one or more elements selected from the group consisting of Fe, Mn, and Cr, 
 wherein the Z is one or more elements selected from the group consisting of Si, Al, Ga, and Ge, and 
 wherein α+β>2 is satisfied. 
 
     
     
       10. The magnetoresistance effect element according to  claim 9 , wherein the Y is Fe, and the Z is Ga and Ge. 
     
     
       11. The magnetoresistance effect element according to  claim 1 ,
 wherein the Heusler alloy layer is represented by a composition formula Co 2 Fe α Ga β1 Ga β2 , and 
 wherein α+β1+β2>2.3, α<β1+β2, 0.5<α<1.9, 0.1≤β1, and 0.1≤β2 are satisfied. 
 
     
     
       12. The magnetoresistance effect element according to  claim 1 , wherein the first region has a crystal structure of a body-centered cubic lattice structure (bcc). 
     
     
       13. The magnetoresistance effect element according to  claim 12 , wherein a lattice matching degree between the Heusler alloy layer and the first region is within 4%.